Switching and power phasing apparatus for automatically forming and despinning an antenna beam for a spinning body



H. A. ROSEN ErAL 3,531,803 SWITCHING AND POWER PHASING APPARATUS FORSept. 29, M70

AUTOMATICALLY FORMING AND DESPINNING AN ANTENNA BEAM FOR A SPINNING BODY7 Sheets-Sheet 5 Filed May 2, 1966 uhmki W N llllllll SQ m llllll ll.

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AUTOMATICALLY FORMING AND DESPINNING AN Filed May 2, 1966 ANTENNA BEAMFOR A SPINNING BODY 7 Sheets-Sheet A 72 1 11 i l l l l -r/Mfi l m- ONEBEVoLUr/DN lNVENTOR-S #43040 ,4. QaazN Evie/'5 Z5u5507/A/ 77400145Z/OSPETH a m wept. 29, I90 H. A. ROSEN HAL 3,531,803

SWITCHING AND POWER PHASING APPARATUS FOR AUTOMATICALLY FORMING ANDDESPINNING AN ANTENNA BEAM FOR A SPINNING BODY Filed May 2, 1966 7Sheets-Sheet 5 H. A. ROSEN ET AL SWITCHING AND POWER PHASING APPARATUSFOR AUTOMATICALLY FORMING AND DESPINNING AN ANTENNA BEAM FOR A SPINNINGBODY 7 Sheets-Sheet 6 Filed May 2, 1966 N v am A M mo p w 2 5 r r Wfw m4D7. 5 a wwfl B SWITCHING AND POWER PHASING APPARATUS FOR AUTOMATICALLYFORMING AND DE- SPINNING AN ANTENNA BEAM FOR A SPIN- NING BODY Harold A.Rosen, Santa Monica, Boris T. Subbotin, Van Nuys, and Thomas Hudspeth,Malibu, Calif., assignors to Hughes Aircraft Company, Culver City,Calif., a corporation of Delaware Filed May 2, 1966, Ser. No. 546,875Int. Cl. H04b 7/00 US. Cl. 343-100 6 Claims ABSTRACT OF THE DISCLOSURE Asystem operable on a spinning body providing a plurality of individuallyexcitable antenna elements with means for both switching and phasingpower to individually operable elements so as to develop optimum gainand directivity. Selected power amplifiers are switched to a selectednumber of adjacent element-s during each predetermined fraction of thespacecraft revolution. As the body rotates, phase shifters adjust the RFphase so that the main beam is pointed in the same direction. After thebody has revolved the predetermined fraction, one of the poweramplifiers is switched to another element at a time when the RF phaseshift is proper for continuous operation.

This invention relates to directive radio and antenna systems forspinning bodies, and more particularly to apparatus for developing astationary radiation beam from a plurality of rotating directive antennaelements.

It is desired to provide a spinning body, such as a communicationsatellite, with a highly directive radiation pattern, such that anydesired area of the globe can be illuminated therefrom. Typical ofhighly directional antenna elements are slotted and open-endedwaveguides. Although it has been known that a circular array of suchantenna elements can be arranged on a spinning body, there hasheretofore been no apparatus for applying R-F excitation currents tosuch elements so as to establish and maintain a radiation pattern in afixed direction.

It is an object of this invention to provide a rotatable body with aplurality of individually excitable antenna elements, and means forexciting such elements so that a radiation pattern in a predetermineddirection is established and maintained.

It is another object of this invention to provide electrical means forswitching and phasing power to individually operable antenna elements ona spinning body so as to provide optimum antenna gain and directivity.

A further object of this invention is to provide a communicationsatellite having individually operable direc tive antenna elementscapable of giving a radiation pattern of any desired elevational andazimuthal dimensions.

Still another object of this invention is to provide a communicationsatellite with highly directive, individually excitable antennaelements, which satellite is characterized as a rugged construction of aminimum number of component parts of simple, lightweight design.

The above and other objects and advantages of this invention will becomeapparent from the following description taken in conjunction with theaccompanying drawings of illustrative embodiments thereof, in which:

FIG. 1 is a top plan view of a circular array of waveguides carried on aspinning satellite, wherein only those waveguides are excited which atany instance are within a sector that is subtended by an angle thatincludes the line toward the earth;

353L803 Patented Sept. 29, 1970 FIG. 2 is a block diagram of the systemof this invention for switching power to different waveguides andphasing the power to each waveguide;

FIG. 3 is a combined block and schematic diagram showing one arrangementof switches through which power is supplied to the individualwaveguides;

FIG. 4 is a block diagram of switching apparatus for controlling theswitches of FIG. 3;

FIGS. Sa-Si illustrate a series of waveforms to aid in explaining theoperation of the switching apparatus of FIG. 4;

FIGS. 6a6h illustrate a series of waveform-s to aid in explaining thephasing of power applied to the wave guides through the switchingapparatus;

FIG. 7 is a perspective view of a circular array of waveguides of a formto provide a radiation pattern of greater elevation than with the arrayof FIGS. 1 and 2;

FIG. 8 is a perspective view of one of the waveguides of FIG. 7;

FIG. 9 is a side elevation view, partly in section, of a biconicalarrangement of open-ended waveguides for operation in accordance withour invention;

FIG. 10 is a side elevation view of a stacked bicone arrangement of ourinvention;

FIG. 11 is an enlarged, fragmentary sectional view of the stackedbicones of FIG. 10, showing the feed to corresponding waveguides of eachbicone;

FIG. 12 is a schematic diagram of another switching apparatus forapplying power from several amplifiers to a single antenna element;

FIG. 13 is a perspective view of one of the magnetically operabletraveling wave switches employed in the switching arrangement of FIG.12;

FIGS. 14-16 are end views of the switch of FIG. 13, to aid in explainingthe operation thereof; and

FIG. 17 is a perspective view of a satellite in which the body andantenna are coextensive.

Referring to FIGS. 1 and 2, there is shown a circular array ofwaveguides 1-16 carried on a spinning body, indicated in phantom linesat 17 Each of the waveguides is provided with a slot 20 in its lateralsurface, an excitation probe or stub 21 extending into the waveguide,and a connection 22 through which to apply power to the probe. In aconventional manner, the satellite is stabilized so that its spin axis25 is parallel to the axis of rotation of the earth. In such stabilizedposition, each of the antenna elements 1-16 rotates past a line 26 inthe direction of the earth, which is the direction in which it isdesired to radiate a beam.

In the example shown, it is desired to excite only those waveguideswhich, at any instant, lie within a predetermined angle which isbisected by the line 26. Such angle is indicated as but obviously may besmaller or larger. It will be apparent that with a given amount ofavailable power, exciting all of the waveguides simultaneously wouldresult in a generally omnidirectional radiation pattern, most of whichwould be wasted. However, utilizing all of the available power to exciteonly those few waveguides within the predetermined sector provides aradiation pattern of high antenna gain and directivity.

At the instant indicated in FIG. 1, the waveguides 1-4 are locatedwithin the selected sector. As will be observed, the satellite isrotating clockwise in FIG. 1, which means that further rotation of thesatellite carries the waveguide 1 out of the sector, and the waveguide 5moves into that sector. Accordingly, power that was applied to thewaveguide 1 must be switched to the waveguide 5.

Furthermore, as each of the waveguides moves through the sector, itsposition relative to the earth is constantly changing, i.e., from amaximum distance as it enters the sector, to a minimum distance when itis on the line 26,

and back to the maximum distance as it leaves the sector. It is desiredto excite each wave-guide as it moves throughout the sector. However, itis essential that all of the excited waveguides be operated so as toproduce a plane phase front moving in the direction of the earth.

A system in accordance with this invention for effecting the desiredswitching and phasing of power applied to waveguides in the designatedsector is shown in FIG. 2. The connections 22 to the various waveguidesextend from switch apparatus 32. As shown, the switch apparatus 32 isadapted to be operated by a switch apparatus control means 33, and tohave power for exciting selected waveguides applied from a network ofpower amplifiers 34. Phasing of the applied power is effected throughcontrollable phase shifters 35, which are driven by phase shifterdriving means including integrators 36 coupled to the control means 33,and wave shapers 37 connected between the integrators 36 and phaseshifters 35. Both the switching and the phasing of the applied power areeffected from a common reference, shown as a reference voltage timingsource 38 that is coupled to the switch apparatus control means 33.

The reference voltage timing source 38 is one which generates a voltageoutput which is referenced to a predetermined position of the satelliteduring each revolution thereof. Examples of suitable reference means forthis purpose are disclosed in US. Pat. No. 3,133,282, Harold A. Rosen,entitled, Apparatus Providing a Rotating Directive Antenna Field PatternAssociated With a Spinning Body, issued May 12, 1964.

In operation, the switch apparatus control means 33 operates the switchapparatus 32 so as to connect those waveguides within the selectedsector to the power amplifiers 34. The outputs of the phase shifters areapplied through the amplifiers 34 and switch apparatus 32 to thosewaveguides in such a manner that the power applied to each waveguide isretarded in phase to a degree depending upon its position within thesector. In this connection, and referring to FIG. 1, phase retardationis a maximum when a waveguide is located on the line 26, and a minimumwhen such waveguide is located at the extremes of the sector. In thismanner, we insure that the radiations from all of the affectedwaveguides are kept in phase, i.e., the plane phase front 30 ismaintained.

Referring to FIG. 3 along with FIG. 2, the phase shifters 35 are shownto comprise four controllable phase shifters 41-44, and the poweramplifiers are shown to include respective power amplifiers 4649 coupledto the phase shifters 4144. The outputs of the power amplifiers 46-49are connected to the inputs of respective magnetically operable switchesa a The respective control coils for the switches a a are indicated at51-54.

Examples of the switches a -a are conventional ferrite circulatorswithces. Such a switch has a pair of output terminals, and its inputcan be connected to one or the other of the output terminals, dependingupon a direction of a current pulse applied to its control coil.

As shown in FIG. 3, the switches a -a are arranged so that correspondingoutput terminals are connected to the input terminals of similarswitches Il -b and c c which also have respective control coils 56-59and 6164. The switch b has one of its output terminals connected to theprobe connection 22 of the waveguide 1 and its other output terminalconnected to the probe connection 22 of the waveguide 9. In similarfashion, the switch 0 has one output terminal connected to the probeconnection of the waveguide 5, and its other output terminal connectedto the probe connection of the waveguide 13.

In this latter connection, the waveguides 1-16 are illustrated in FIG. 3in positions which simplify the explanation of the wiring to theassociated switches. However, it will be recognized that the waveguidesare positioned in the circular array as shown in FIG. 1.

With respect to the waveguides 1, 5, 9 and 13, it will be seen thatthese elements are spaced 90 apart. With reference to FIG. 1, thewaveguide 5 enters the sector when the waveguide 1 leaves it; thewaveguide 9 enters the sector when the waveguide 5 leaves; and thewaveguide 13 enters the sector when the waveguide 9 leaves.

The same arrangement is illustrated for the remaining waveguides. Theswitch b; has its output terminal connected to the probes of thewaveguides 2, 10; the output terminals of the switch b are connected tothe probes of the waveguides 3, 11; and the switch 12 has its outputterminals connected to the probes of the waveguides 4, 12. In a similarmanner, the switch 0 has its output terminals connected to the probes ofthe waveguides 6, 14; the switch 0 has its output terminals connected tothe probes of the waveguides 7, 15; and the switch 0 has its outputterminals connected to the probes of the wave guides 8, 16.

Referring to the first group of switches :1 b 0 let it be assumed thatwhen the control coil 51 of the switch a is pulsed with a positivepulse, the iput of the switch a is connected to the input of switch [1When the coil 51 receives a negative pulse, the input of the switch a isconnected to the input of the switch c In like manner, positive andnegative pulses applied to the control coil 56 of the switch b switchesits input, respectively, to the Waveguide 1 and waveguide 9. In similarfashion, positive and negative pulses supplied to the control coil 61 ofthe switch 0 causes its input to be connected, respectively, to thewaveguide 5 and the waveguide 13.

When the waveguide 5 leaves and the waveguide 9 enters the sector, apositive pulse is applied to the control coil 51 of the switch a and anegative pulse is applied to the control coil 56 of the switch b therebyconnecting the output of the power amplifier 46 to the waveguide 9.Then, when the Waveguide 9 leaves and the Waveguide 13 enters thesector, a negative pulse is applied to the control coil 51 of the switcha and a negative pulse is applied to the control coil 61 of the switch 0thereby to connect the probe of the waveguide 13 to the power amplifier46.

The same sequence of pulses is generated for the remaining groups ofswitches, and the associated waveguides are excited in the-same mannerand in the same sequence. However, the pulses applied to the switches ofthe second group of switches (1 b 0 are generated at times followingthose for the corresponding ones of the first group of switches whichamount to of a revolution of a satellite. Similarly, the pulses appliedto the third group of switches are delayed by another A of a revolution,and those applied to the fourth group of switches are generated stillanother of a revolution later.

One means for effecting the desired switching is illustrated in FIG. 4.A pulse source is provided for generating sixteen unidirectional pulsesper revolution of the satellite. The power source 70 is triggered by thereference voltage timing source 42. The pulses are applied to a networkof flip-flops, each of which is characterized in that successivepositive-going voltages applied thereto cause it to change state and inthat it has two outputs in which the voltages vary oppositely, and whichwill be referred to hereafter as the normal and the conjugate outputs.Referring to FIG. 5, along with FIG. 4, FIG. 5a shows the alternatingsquarewave voltage 72 appearing at one output 73 of the flip-flop 71.

The voltage 72, which will be recognized as an 8- cycle Wave asreferenced to a revolution of satellite, is applied to a similarflip-flop 74. The conjugate squarewave voltage is also applied toanother flip-flop 75. FIG. 5b illustrates a squarewave voltage 77 in thenormal output of flip-flop 74 that is formed in response to the voltage72. As shown, the voltage 77 is of half the frequency of the voltage 72.

The voltage 77 is applied to the input of a flip-flop 78 which similarlydevelops normal and conjugate squarewave voltages 80, 81 (FIGS. 5c and5e) and these in turn are applied to flip-flops 82, 83 to developfurther squarewaves 84, (FIGS 5 511).

With reference to FIG. 5c, it will be seen that two cycles of thevoltage 80 occur during each revolution of the satellite. This normaloutput of the flip-flop- 7 8 is applied also to a pulse-shaping network(FIG. 4) which differentiates the voltage 80 and develops alternatepositive and negative pulses 91-9 4 (FIG. 5d). The output of thepulse-shaping network 90 is applied through a driver amplifier to thecontrol coil 51 of the switch a Thus, in accordance with the sequencepreviously mentioned, positive and negative pulses are alternatelyapplied to the control coil 51 to alternately switch 11 between itsoutput terminals, i.e., alternately connecting the input of switch a tothe inputs of the switches [2 C1.

Again referring to FIG. 5, and particularly to FIGS. 5 and 5h, one cycleof each of the voltages 84, 85 occurs during each revolution of thesatellite. However, the voltages 84, 85 are 90 out of phase, the voltage85 lagging the voltage 84 by 90. The voltage 84 from the flip-flop 82 isapplied to a pulse-shaping network 98 which differentiates the voltage84 and develops alternate positive and negative pulses 99, 100 (FIG. 5These pulses are applied through a driver amplifier 101 to the controlcoil 56 of the switch b Thus, the positive pulse 99 is applied to thecontrol coil 56 of the switch 11 when the positive pulse 91 is appliedto the control coil 51 of switch a thereby connecting the poweramplifier 46 to the waveguide 1. A half revolution later, when thepositive pulse 93 is applied to the control coil 51 of the switch a thenegative pulse 100 is applied to the control coil 56 of the switch bthereby connecting the amplifier 41 to the waveguide 9.

The voltage '85 from the flip-flop 83 is applied to a pulse-shapingnetwork 104, which difierentiates the wave and develops alternatepositive and negative pulses 105, 106. Like the pulses 99, 100, thepulses 105, 106 are spaced a half revolution apart. However, as with thevoltages from which they were developed, the pulse 105 is spaced aquarter of a revolution from the pulse 99, and the pulse 106 is spaced aquarter of a revolution from the pulse 100.

The output of the pulse-shaping network 104 is applied through a driveramplifier 107 to the control coil 61 of the switch 0 Accordingly, itwill be seen that when the negative pulse 92 is applied to the controlcoil 51 of the switch a the positive pulse 105 is applied to the controlcoil 6-1 of the switch c thereby connecting the power amplifier 46 tothe probe of the waveguide 5. Similarly, when the negative pulse 94 isapplied to the control coil 51 of the switch a the negative pulse 106 isapplied to the control coil 61 of the switch c thereby connecting theamplifier 46 to the prove of the waveguide 13.

The same arrangement of flip-flops, pulse-shaping networks and driveramplifiers is employed for pulsing the remaining groups of switches sothat each of the waveguides served thereby is connected to its poweramplifier for the portion of each revolution in which it is movingthrough the sector. In this connection, the input to a flipfiop 110 isconnected to the normal output of the flip-flop 75, and flip-flops 111,112 are connected to the outputs of the flip-flop 110, all in the samemanner as the flip-flops 78, 82, 83. Inasmuch as the 8-cycle voltageapplied to the flip-flop 75 is the conjugate of the voltage 72 of FIG.5a, the waveform of the voltage applied to the fiip-flop 110 is the sameas that of the voltage 77 of FIG. 5b, but displayed by of a revolution.Since the outputs of the flip-flops 110-112 are connected throughpulse-shaping networks and driver amplifiers to the control coils of theswitches a b 0 in the same manner as the first group of switches, theassociated waveguides 2, 6, 10, 14 areexcited in the same sequence for aquarter of a revolution,

but at times A of a revolution after the corresponding waveguides in thefirst group 1, 5, 9, 13 are excited.

The conjugate voltages from flip-flops 74, 75 are utilized in the samemanner for operating the remaining groups of switches a [1 c and (1 b 0For example, the inverted voltage from the flip-flop 74 is applied tothe input of a fllp-flop 114, the outputs of which are applied tosimilar flip-flops 115, 116. The conjugate voltage from the flip-flop 74is displaced by V of a revolution from the normal voltage from theflip-flop 75. Since the flip-flops 114-116 are connected throughpulse-shaping networks and driver amplifiers to the control coils of theswitches a b 0 in the same manner as previously described for the firstgroup of switches, the switches a b 0 are operated to connect theassociated waveguides 3, 7, 11, 15 to the associated power amplifier inthe same sequence.

Rounding out the foregoing, the conjugate output of the flip-flop 75 isconnected to the input of a flip-flop 117, the outputs of which areconnected to similar flip-flops 118, 119. As will now be apparent, theflip-flops 117-119 operate in the same manner as the flip-flops 114-116,thereby to cause the switches a b c to be operated for connecting theassociated waveguides 4, 8, 12, 16 to the associated power amplifier inthe same sequence.

As previously explained in connection with FIGS. 2 and 3, the phaseshifters 41-44 are adapted to retard the phase of the r-f currentsapplied to each excited waveguide as it moves through the sector.Referring to FIG. 6 along with FIG. 4, there is illustrated a squarewavevoltage 120 which, during each quarter of a revolution, decreases fromzero to a minimum, and back to zero. The voltage 120 is applied to thephase shifter 41, which responds thereto to variably retard the phase ofthe power applied to each of the waveguides 1, 5, 9, 13 as it movesthrough the sector. The point of maximum phase retardation occurs at themidpoint of each of the excursions of the voltage 120. In thisconnection, each of the waveguides 1, 5, 9, 13 is shown adjacent thelobe of the voltage 120 applied to that waveguide.

In similar fashion, FIGS. 6d, 6 and 6h illustrate the voltage waveforms121-123 applied to the phase shifters 42-44 for changing the phase ofthe power applied to each associated waveguide as it moves through thesector.

Referring to FIG. 4, along with FIG. 6, the phasing voltages 120-123 areobtained from the outputs of the flip-flops 74, 75. In this connection,FIG. 6a shows the voltage waveform 125 that is the conjugate output ofthe flip-flop 74. The voltage 125 is applied to an integrator 126 whichdevelops an integrated output voltage, indicated as a dotted waveform127 in FIG. 6a. The integrated voltage 127 is applied to a wave shaper129 to develop the voltage 120 of FIG. 6b. In response to such voltage,as previously explained, the phase shifter 41 functions to vary thephase of the rcurrents applied to the respective waveguides 1, 5, 9, 13served thereby.

As will now be apparent, the voltages 121-123 are derived in similarfashion. FIG. 60 shows the conjugate voltage wave 131 from the flip-flop75, and a corresponding integrated voltage 132 from which the voltagewave 121 of FIG. 6d is derived. To this end, it will be obvious frominspection of FIG. 4 that the conjugate output of the flipflop 75 isapplied to an appropriate integrator and Wave shaper coupled to thephase shifter 42 of FIG. 3.

FIG. 6e shows the normal output voltage 77 from the flip-flop 74 (whichis the same voltage shown in FIG. 5 b). This voltage is similarlyintegrated to obtain the integrated voltage 134, and thence the voltage122 of FIG. 61. In like manner, FIG. 6g shows the normal output voltage136 of the flip-flop 75, and integrated voltage 137 derived therefrom,from which the voltage 123 is obtained.

An array of directive antenna elements as heretofore described can beprovided in any desired number, and the sector in which waveguides areexcited can be mad a large or as small as necessary to establish thedesired beam coverage on the earth. In this connection, and referring toFIGS. 1 and 2, waveguides with as narrow a sector as necessary areexcited to provide an azimuthal beam of wide coverage, e.g., half thelobe. The single aperture waveguides also provide broad elevation (i.e.,north-south) coverage. However, while waveguides in a large sector canbe excited to provide extremely narrow azimuthal coverage, thesingle-aperture waveguides of FIGS. 1 and 2 are limited to broadelevation coverage.

FIGS. 7-11 illustrate circular arrays of waveguides to obtain narrowcoverage in both azimuth and elevation. Referring to FIG. 7, a circulararray of antenna elements is formed of elongated waveguides 141 carriedon a satellite 142. Along its length, each of the waveguides 141 has aplurality of slots 143 formed in its outer wall. The slots 143 may beformed in any desired shape and arrangement, e.g., two rows of staggeredrectangular slots as indicated in the example shown. Elongatedstationary waveguides having a plurality of slots therein are well knownin the art. As is conventional, however, the slots 143 are arranged,e.g., one wavelength vertical spacing between slots in each row andsuitable spacing, e.g., one-eighth, between the rows of each pair, andthe spacing and arrangement is such as to insure that the radiationstherefrom are in phase along the length of the waveguide. As shown inFIG. 8, each of the waveguides 141 is provided with means to excite itindividually, e.g., a coaxial connection 144 leading to a connector 145for an internal probe (not shown).

With the elongated array of antenna elements 141 of FIG. 7 substitutedfor the waveguides 1-16 of FIGS. 1 and 2, it will be seen that, whilethe elements 141 are excited individually as previously described, theresulting elevation beam width is considerably narrower. With waveguides141 of sufficient length, which may be of the order of ten wavelengths,a resulting antenna pattern may be obtained in which coverage isconfined to a small area on the globe.

FIG. 9 illustrates another antenna construction for a satellite inaccordance with our invention. The construction shown in FIG. 9 is abicone antenna, wherein a circular array of antenna elements is formedof openended waveguides 146. As shown, each of the waveguides 146 isformed as an elongated element having its open end bent at right angles.The resulting circular array of waveguide mouths is located between thesmall ends of oppositely facing frusto-conical reflectors 147, 148. Inthis connection, the diameters of the inner ends of the conical elements147, 148 are the same as the outer diameter of the circle formed by themouths of the waveguides 146.

The waveguides 146 are shown to be supported at their lower ends by thebody of the satellite 150. With this antenna arrangement substituted forthat in FIGS. 1 and 2, the radiation pattern obtained is one in whichthe reflectors 147, 148 provide broad coverage in elevation. However,such coverage is considerably narrower than is obtainable without thereflectors. In this connection, the flare angle, 0, between thediverging reflectors, together with the outer diameters of the largeends of the reflectors, determines the gain and directivity of the beam.

Our invention also includes the feature of stacked bicone antennaarrangements of the type shown in FIG. 9. Referring to FIGS. and 11,there is shown a stack of four such bicones supported by the satellitebody 150, and in which four circular arrays of open-ended waveguides152-155 are located between respective pairs of diverging frusto-conicalreflectors 157-158, 159-160, 161-162, 163-164. The open ends of the waveguides in the stack are aligned, and each aligned set is connected to acommon feed. To this end, a coaxial or waveguide fed may be employed.For example, as best seen in FIG. 11, a corporate waveguide feed may beemployed in which aligned openings 152., 153 in the upper pair areconnected at 166, aligned openings 154, 155 in the lower pair areconnected at 167, the connections 166, 167 are connected at 168, and theconnection 168 is connected at 169 to an energizing source (not shown).The input 169 to this feed corresponds to a probe connection 22 in FIGS.1 and 2.

With such a stacked bicone antenna arrangement substituted for the arrayof waveguides in FIG. 2, it will be seen that we obtain a radiationfield pattern which is extremely narrow both in elevation and inazimuth. With such a stacked bicone arrangement, for an equivalentbeamwidth the various reflectors employed may be considerably smaller indiameter than those required where only a single bicone arrangement (asin FIG. 9) is used.

It will be apparent to persons of ordinary skill in the art that avariety of the switching schemes may be employed for the switchingapparatus, and that our invention is not limited to the particularswitching scheme above described. Additionally, our invention embracesthe use of switching devices other than the ferrite circulator switchespreviously described, and means for applying increased power to eachdirective antenna element as it moves through the predetermined sector.

FIGS. 12-16 illustrate one switching arrangement of the type referredto, and in which different switch mechanisms are employed, and in whichpower from a plurality of amplifiers is applied to a single waveguide asit moves through the predetermined sector. Referring to FIG. 12, thereis shown two pairs of power amplifiers, 171, 172 and 173, 174 having acommon input, as from one of the phase shifters heretofore described.The outputs of the amplifiers 171, 172 are connected to the inputterminals 175, 176 of a switch 177 from which all of the power from bothamplifiers 171, 172 is made to appear at either of a pair of outputterminals 178, 179. In similar fashion, the outputs of the amplifiers173, 174 are applied to corresponding input terminals 180, 181 of asimilar switch 182, which is operable to cause the power from bothamplifiers 173, 174 to be applied to either of a pair ofoutput terminals183, 184 of the switch 182.

As shown, respective output terminals 179, 183 of the switches 177, 182are connected to respective input connections of a conventional hybridelement 187 which has respective output terminals 188, 189 connected tothe probes of respective waveguides 1, 9. In the same manner, theremaining output terminals 178, 184 of the switches 177, 182 areconnected to input terminals 195, 196 of a similar hybrid element 197,from which respective outputer terminals 198, 199 are connected to theprobes of respective waveguides 5, 13.

Referring to the hybrid 187, it is a passive element which functions sothat when the power from the amplifiers 171, 172 is applied to thehybrid input terminal 185 and the power from the amplifiers 173, 174 isapplied to the hybrid input terminal 186, the power from all fouramplifiers appears at either the output terminal 188 or the outputterminal 189, depending upon whether the power appearing at the inputterminals 185, 186 is in phase or 180 out of phase.

The hybrid 197 operates in the identical manner of the hybrid 187.Accordingly, if the combined outputs of the amplifiers 171, 172 are madeto appear at the input terminal 195, and the combined outputs of theamplifiers 173, 174 are made to appear at the input terminal 196, thecombined power from all of the amplifiers is made to appear at theoutput terminal 198 or the output terminal 199, depending upon whetherthe power inputs at the terminals 195, 196 are in phase or 180 out ofphase.

FIGS. 13-16 illustrate the general construction of switches 177, 182,and their mode of operation. Referring to FIG. 13, which depicts theswitch 177, the device employs a tube 200 having power input terminals175, 176 at one end which are displaced Positioned at the opposite endof the tube are output probes 178, 179 which are also displaced 90.However, the output probes 9 178, 179 are angularly displaced about 45from the input probes 175, 176, such that one of the output probes 178is located midway between the input probes 175, 176.

Disposed within the tube 200 is a ferrite element 205, and surroundingthe tube intermediate the ends of the element 205 is an energizing coil206.

With the arrangement illustrated in FIG. 13, the application of equal,in phase power to the input probes :175, 176 causes a field to beestablished in the tube 200 which is represented by an electric vector,indicated by arrow 208, that is centered between the input probes 175,176. Referring to FIG. 14, along with FIG. 13, the wave thus estabilshedtravels through the tube 200, and is coupled to one or the other of theoutput probes 178, 179, depending upon the application or absence of acurrent in the coil 206. For example, if no current is applied to thecoil 206, the wave travels through the tube without being shifted, inwhich case the arrow 208 (FIG. 14) indicates that all of the power iscoupled to the upper output probe 178.

Current in one direction through the coil 206 causes the field to berotated 90, and the direction of such rotation will depend upon thedirection of current flow through the coil. In either case, all of thepower is coupled into the other output probe 179.

In this latter connection, FIG. 15 illustrates a situation in whichcurrent is fed through the coil 206' in one direction, and FIG. 16illustrates the situation in which such current is in the oppositedirection. In FIGS. 15 and 16, the arrow 208 is shown in reversedpositions, although aligned with the output probe 179, to illustrate the180 phase shift resulting from current flow in opposite directionsthrough the coil 206.

Referring again to FIG. 12, the control coil for the switch 182 isindicated at 210. To better understand the combined operations of theswitches 177, 18 2, let it be assumed that no current flows in the coil210 of the switch 1 82, thereby causing the combined output of theamplifiers 173, 174 to appear at the output terminal 183, and hence atthe input terminal 186 of the hybrid 1187. Also, let it be assumed thatcurrent is applied to the coil 206 is such a direction as to cause thecombined outputs of the amplifiers 171, 1721 to appear at the outputterminal 179 of switch 177, and hence at the input terminal 185 of thehybrid 187.

For the assumed direction of flow of current through the coil 206, thecombined input at the hybrid input terminals 185, 1 86 is caused toappear at one of its output terminals 18 8. Reversing the direction ofcurrent flow to the coil 206 causes the combined input at 185, 186 toappear at the other output terminal 189.

Operation of the switches 177, 182 to couple the com bined outputs ofthe amplifiers 171-114- to either of the outputs of the hybrid 197 iseffected in the same manner. In such case, there is no current in thecoil 206 of the switch 177, and there is current in the coil 210 of theswitch .182, thereby causing the outputs of the amplifiers '171, 172 toappear at the output terminal 178 and hence the input terminal 195 ofthe hybrid 197, and causing the outputs of the amplifiers 173, 174 toappear at the output terminal 184, and hence the hybrid input terminal196. For one direction of current flow through the coil 210, thecombined outputs of the four amplifiers are made to appear at one of thehybrid output terminals, e.g., the terminal 198. For the oppositedirection of current flow through the coil 210, such combined outputsare made to appear at the other output terminal 199.

In the antenna arrangements heretofore described, it will be noted thatthe surface area of the total satellite is shared between the antennaarray and the satellite body. In this connection, the satellite body inconventional fashion carries on its outer surface a plurality of stripsof solar cells, which provide the power for all electrically operatedequipment. The major portion of the power pro- 10 vided by such solarcells is used to drive the power amplifiers.

Further in this connection, with the total surface of the satelliteshared between the antenna array and the remainder of thesatellite-which includes the solar cellsa relatively broad antennapattern, e.g., suflicient to encompass the globe, can be obtained withrelatively small antenna elements. In such case, the bulk of the lateralsurface of the satellite can be utilized for solar cells for supplyingthe desired power.

A larger surface must be occupied by the antenna on a satellite in whicha relatively small area of the globe is to be covered by the radiationpattern. Thus, elongated antenna arrays as heretofore described inconnection with FIGS. 7ll, result in a small portion of the satellitebeing available for the solar cells. Accordingly, it will be seen thatthere are practical limits to the proportions of the satellite volumethat can be taken up by the antenna structure and the solar cellsupporting structure. As a practical matter, there is a measure ofequivalency between antenna aperture and surface area that must beallotted to solar cells sufficient to provide the R-F power necessaryfor the antenna beam.

Referring to FIG. 17, a satellite in accordance with our invention isshown in which the same surface area is utilized for both the antennaarray and the solar cells. There is shown a circular array of elongateddirectional waveguide elements 211, each of which is provided withparallel rows of staggered slots 212, 213, much as in the antenna arrayshown in FIGS. 7 and 8. Surrounding this entire array, and coextensivetherewith, is an electrically insulating sleeve 214. The sleeve 214 maybe formed of any suitable material, such as a plastic or fiberglassmaterial commonly used as substrates on which solar cells areconventionally mounted on satellites, and is transparent to R-F energy.

Attached to the exterior of the sleeve 214 are a plurality of spacedstrips 215 of solar cells. As illustrated, each of the strips 215 islocated between adjacent rows of slots 212, 213 of adjacent waveguides.The edges of the strips 215 do not extend to the slots, but are spacedtherefrom so as to avoid interference with the radiation patternemitted.

Such an arrangement is one in which approximately percent of the totalsurface area of the satellite is occupied by solar cells. Moreover, theentire length and diameter of the satellite is available for purposes ofestablishing a radiation field pattern for obtaining an elevationbeamwidth of any desired size. Still further, it will be recognized thatthe satellite carries within the interior of the waveguide array theelectrical equipment heretofore mentioned for obtaining the desiredazimuthal beamwidth, including the switching apparatus, control means,power amplifiers, etc. In addition, of course, this composite satellite,in the same manner as conventional satellites, supports within itsinterior the equipment necessary to perform various physical andelectrical functions normally required of such devices. In this latterconnection, there is shown in FIG. 17 the nozzle 216 of an apogee motor219, such motor being mounted in the space defined by the interior wallsof the waveguides 211. Also, there is shown extending from the lower endof the satellite structure a number of telemetry and/ or command VHFantennas 217.

Connections from the solar cell strips 215 may be led into the interiorof the composite satellite of our invention in any suitable manner. Forexample, such connections may extend around the ends of the antennaelements 211. Alternatively, the may be led into the interior betweenadjacent elements.

While there have been shown and described certain types of switches andswitching schemes, our invention clearly embraces reasonable equivalentsthereof. For example, we recognize that analog equivalents of digitalswitching as described herein may be employed, e.g., a

butter matrix replacing the switching elements and having respectiveinputs connected to the power amplifiers and respective outputsconnected to the antenna elements so as to form the beam. Persons ofordinary skill in the art can readily determine the voltage waveformsnecessary for creating the phase shifters for despinning the beam.

Accordingly, we do not intend that the scope of our invention shall belimited, except in accordance with a reasonable interpretation of theappended claims.

What is claimed is:

1. In combination:

a circular array of directive antenna elements adapted to be rotated;

controllable phase shifting means through which to apply power to saidantenna elements;

power amplifiers coupled to said phase shifting means;

switching means coupled between said power amplifiers and said antennaelements;

first control means for selectively operating said phase shifting meansto cause the power applied to said antenna elements to be so phased thata predetermined radiation pattern is radiated in a selected directionfrom a predetermined sector of said array through which said antennaelements are rotated;

second control means coupled to said switching means to connect saidantenna elements in said sector to said power amplifiers;

and a source of reference signals related to the rotation angle of saidcircular array and coupled to said second means to switch an antennaelement into said sector and antenna element out of said sector at eachpredetermined fraction of revolution of said array.

2. The combinaton of claim 1, including means having a plurality ofbistable means for operating said switching means and coupled to saidfirst means for controlling said phase shifting means in synchronisrnwith said switching means.

3. A communication device comprising:

a body adapted to revolve about an axis and including means to provide areference signal representing the angular position of said body;

a circular array of directive antenna elements about said axis, eachantenna element being adapted to be separately excited and each elementrepresenting a predetermined angle of a revolution of said body;

controllable phase shifting means adapted to have power for the antennaelements applied thereto;

switching apparatus coupled between said antenna elements and said phaseshifting means;

switch apparatus control means coupled to said phase shifting means andto said switch apparatus, said control means switching said antennaelements in a predetermined sequence to maintain a selected number ofexcited adjacent elements;

and a reference voltage timing source coupled to said control means,said control means responding to said reference signal to operate saidswitch apparatus to cause power to be applied to said selected number ofantenna elements so that each element passes energy during apredetermined angle of revolution and to operate said phase shiftingmeans to form a selected radiation pattern.

4. A communication device comprising:

a circular array of directive antenna elements, each including means tobe individually excited, said array being adapted to be rotated aroundan axis;

reference means for developing a signal representing the angularposition of said device;

exciting means for said antenna elements;

and means responsive to said reference means to connect said excitingmeans to a predetermined number of said antenna elements by sequentiallyconnecting an antenna element and disconnecting a different antennaelement in a direction opposite but equal to said direction of rotation,whereby to cause a stationary antenna filed pattern to be radiated in aselected direction from a predetermined sector through which said arrayrotates.

5. A communication device as defined in claim 4, wherein said excitingmeans includes controllable phase shifting means;

means for applying signals to said phase shifting means;

switch apparatus in said connecting means coupled between said phaseshifting means and said antenna elements;

and control means for operating said switch apparatus to selectivelyconnect said phase shifting means to said antenna elements so'thatduring each revolution of said array a different element is connectedand a difierent element is disconnected each predetermined fraction ofrevolution.

6. A communication device as defined in claim 4 wherein said connectingmeans causes each antenna element to be excited in its movementthroughout the predetermined sector and wherein a plurality of antennaelements are located in the predetermined sector at any instant, andwherein said connecting means causes said exciting means to besimultaneously connected to each of said plurality of antenna elementslocated in said sector.

References Cited UNITED STATES PATENTS 2,711,533 6/1955 Litchford343-774 X 3,133,282 5/1964 Rosen 343100 3,145,352 8/1964 Russell 343-854X 3,151,326 9/1964 Ohm 343-100 3,196,438 7/1965 Kompfner 343100 RODNEYD. BENNETT, Primary Examiner M. F. HUBLER, Assistant Examiner

